25th International Spin Symposium (SPIN 2023)

A new distributed Bragg reflector for MOCVD-grown spin polarized electron sources

Sep 28, 2023, 7:00 PM

2h

Grand Ballroom I (Durham Convention Center)

Poster Polarized Ion and Lepton Sources and Targets Poster Session

Speaker

Dr Sylvain Marsillac (Old Dominion University)

Description

Photocathodes fabricated with a distributed Bragg reflector have been known to provide higher quantum efficiency, because the light entering the photocathode can reflect many times between the DBR and the front surface of the photocathode, providing more absorption of the incident laser light. Our team previously demonstrated enhanced quantum efficiency from a DBR photocathode using the process of molecular beam epitaxy (MBE), with the DBR composed of multiple layer pairs of AlAs0.61P0.39/ GaAs0.65P0.35. In this work, we report excellent results from a photocathode fabricated via metal organic chemical vapor deposition (MOCVD), and with the DBR composed of In0.30 Al0.70/ GaAs0.65P0.35. Overall, our devices achieved up to 82% polarization and 2.9% quantum efficiency. This presentation describes fabrication issues related to MOCVD, the benefits of this new DBR structure and prospects for higher quantum efficiency.